MFV r319945,r319946: 8264 want support for promoting datasets in libzfs_core

[FreeBSD/FreeBSD.git] / contrib / llvm / tools / lldb / include / lldb / Symbol / ObjectFile.h

//===-- ObjectFile.h --------------------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#ifndef liblldb_ObjectFile_h_
#define liblldb_ObjectFile_h_

#include "lldb/Core/DataExtractor.h"
#include "lldb/Core/FileSpecList.h"
#include "lldb/Core/ModuleChild.h"
#include "lldb/Core/PluginInterface.h"
#include "lldb/Host/Endian.h"
#include "lldb/Host/FileSpec.h"
#include "lldb/Symbol/Symtab.h"
#include "lldb/Symbol/UnwindTable.h"
#include "lldb/lldb-private.h"

namespace lldb_private {

class ObjectFileJITDelegate {
public:
  ObjectFileJITDelegate() {}

  virtual ~ObjectFileJITDelegate() {}

  virtual lldb::ByteOrder GetByteOrder() const = 0;

  virtual uint32_t GetAddressByteSize() const = 0;

  virtual void PopulateSymtab(lldb_private::ObjectFile *obj_file,
                              lldb_private::Symtab &symtab) = 0;

  virtual void PopulateSectionList(lldb_private::ObjectFile *obj_file,
                                   lldb_private::SectionList &section_list) = 0;

  virtual bool GetArchitecture(lldb_private::ArchSpec &arch) = 0;
};

//----------------------------------------------------------------------
/// @class ObjectFile ObjectFile.h "lldb/Symbol/ObjectFile.h"
/// @brief A plug-in interface definition class for object file parsers.
///
/// Object files belong to Module objects and know how to extract
/// information from executable, shared library, and object (.o) files
/// used by operating system runtime. The symbol table and section list
/// for an object file.
///
/// Object files can be represented by the entire file, or by part of a
/// file. An example of a partial file ObjectFile is one that contains
/// information for one of multiple architectures in the same file.
///
/// Once an architecture is selected the object file information can be
/// extracted from this abstract class.
//----------------------------------------------------------------------
class ObjectFile : public std::enable_shared_from_this<ObjectFile>,
                   public PluginInterface,
                   public ModuleChild {
  friend class lldb_private::Module;

public:
  typedef enum {
    eTypeInvalid = 0,
    eTypeCoreFile,      /// A core file that has a checkpoint of a program's
                        /// execution state
    eTypeExecutable,    /// A normal executable
    eTypeDebugInfo,     /// An object file that contains only debug information
    eTypeDynamicLinker, /// The platform's dynamic linker executable
    eTypeObjectFile,    /// An intermediate object file
    eTypeSharedLibrary, /// A shared library that can be used during execution
    eTypeStubLibrary, /// A library that can be linked against but not used for
                      /// execution
    eTypeJIT, /// JIT code that has symbols, sections and possibly debug info
    eTypeUnknown
  } Type;

  typedef enum {
    eStrataInvalid = 0,
    eStrataUnknown,
    eStrataUser,
    eStrataKernel,
    eStrataRawImage,
    eStrataJIT
  } Strata;

  //------------------------------------------------------------------
  /// Construct with a parent module, offset, and header data.
  ///
  /// Object files belong to modules and a valid module must be
  /// supplied upon construction. The at an offset within a file for
  /// objects that contain more than one architecture or object.
  //------------------------------------------------------------------
  ObjectFile(const lldb::ModuleSP &module_sp, const FileSpec *file_spec_ptr,
             lldb::offset_t file_offset, lldb::offset_t length,
             const lldb::DataBufferSP &data_sp, lldb::offset_t data_offset);

  ObjectFile(const lldb::ModuleSP &module_sp, const lldb::ProcessSP &process_sp,
             lldb::addr_t header_addr, lldb::DataBufferSP &data_sp);

  //------------------------------------------------------------------
  /// Destructor.
  ///
  /// The destructor is virtual since this class is designed to be
  /// inherited from by the plug-in instance.
  //------------------------------------------------------------------
  ~ObjectFile() override;

  //------------------------------------------------------------------
  /// Dump a description of this object to a Stream.
  ///
  /// Dump a description of the current contents of this object
  /// to the supplied stream \a s. The dumping should include the
  /// section list if it has been parsed, and the symbol table
  /// if it has been parsed.
  ///
  /// @param[in] s
  ///     The stream to which to dump the object description.
  //------------------------------------------------------------------
  virtual void Dump(Stream *s) = 0;

  //------------------------------------------------------------------
  /// Find a ObjectFile plug-in that can parse \a file_spec.
  ///
  /// Scans all loaded plug-in interfaces that implement versions of
  /// the ObjectFile plug-in interface and returns the first
  /// instance that can parse the file.
  ///
  /// @param[in] module
  ///     The parent module that owns this object file.
  ///
  /// @param[in] file_spec
  ///     A file specification that indicates which file to use as the
  ///     object file.
  ///
  /// @param[in] file_offset
  ///     The offset into the file at which to start parsing the
  ///     object. This is for files that contain multiple
  ///     architectures or objects.
  ///
  /// @param[in] file_size
  ///     The size of the current object file if it can be determined
  ///     or if it is known. This can be zero.
  ///
  /// @see ObjectFile::ParseHeader()
  //------------------------------------------------------------------
  static lldb::ObjectFileSP
  FindPlugin(const lldb::ModuleSP &module_sp, const FileSpec *file_spec,
             lldb::offset_t file_offset, lldb::offset_t file_size,
             lldb::DataBufferSP &data_sp, lldb::offset_t &data_offset);

  //------------------------------------------------------------------
  /// Find a ObjectFile plug-in that can parse a file in memory.
  ///
  /// Scans all loaded plug-in interfaces that implement versions of
  /// the ObjectFile plug-in interface and returns the first
  /// instance that can parse the file.
  ///
  /// @param[in] module
  ///     The parent module that owns this object file.
  ///
  /// @param[in] process_sp
  ///     A shared pointer to the process whose memory space contains
  ///     an object file. This will be stored as a std::weak_ptr.
  ///
  /// @param[in] header_addr
  ///     The address of the header for the object file in memory.
  //------------------------------------------------------------------
  static lldb::ObjectFileSP FindPlugin(const lldb::ModuleSP &module_sp,
                                       const lldb::ProcessSP &process_sp,
                                       lldb::addr_t header_addr,
                                       lldb::DataBufferSP &file_data_sp);

  static size_t GetModuleSpecifications(const FileSpec &file,
                                        lldb::offset_t file_offset,
                                        lldb::offset_t file_size,
                                        ModuleSpecList &specs);

  static size_t GetModuleSpecifications(const lldb_private::FileSpec &file,
                                        lldb::DataBufferSP &data_sp,
                                        lldb::offset_t data_offset,
                                        lldb::offset_t file_offset,
                                        lldb::offset_t file_size,
                                        lldb_private::ModuleSpecList &specs);
  //------------------------------------------------------------------
  /// Split a path into a file path with object name.
  ///
  /// For paths like "/tmp/foo.a(bar.o)" we often need to split a path
  /// up into the actual path name and into the object name so we can
  /// make a valid object file from it.
  ///
  /// @param[in] path_with_object
  ///     A path that might contain an archive path with a .o file
  ///     specified in parens in the basename of the path.
  ///
  /// @param[out] archive_file
  ///     If \b true is returned, \a file_spec will be filled in with
  ///     the path to the archive.
  ///
  /// @param[out] archive_object
  ///     If \b true is returned, \a object will be filled in with
  ///     the name of the object inside the archive.
  ///
  /// @return
  ///     \b true if the path matches the pattern of archive + object
  ///     and \a archive_file and \a archive_object are modified,
  ///     \b false otherwise and \a archive_file and \a archive_object
  ///     are guaranteed to be remain unchanged.
  //------------------------------------------------------------------
  static bool SplitArchivePathWithObject(
      const char *path_with_object, lldb_private::FileSpec &archive_file,
      lldb_private::ConstString &archive_object, bool must_exist);

  //------------------------------------------------------------------
  /// Gets the address size in bytes for the current object file.
  ///
  /// @return
  ///     The size of an address in bytes for the currently selected
  ///     architecture (and object for archives). Returns zero if no
  ///     architecture or object has been selected.
  //------------------------------------------------------------------
  virtual uint32_t GetAddressByteSize() const = 0;

  //------------------------------------------------------------------
  /// Get the address type given a file address in an object file.
  ///
  /// Many binary file formats know what kinds
  /// This is primarily for ARM binaries, though it can be applied to
  /// any executable file format that supports different opcode types
  /// within the same binary. ARM binaries support having both ARM and
  /// Thumb within the same executable container. We need to be able
  /// to get
  /// @return
  ///     The size of an address in bytes for the currently selected
  ///     architecture (and object for archives). Returns zero if no
  ///     architecture or object has been selected.
  //------------------------------------------------------------------
  virtual lldb::AddressClass GetAddressClass(lldb::addr_t file_addr);

  //------------------------------------------------------------------
  /// Extract the dependent modules from an object file.
  ///
  /// If an object file has information about which other images it
  /// depends on (such as shared libraries), this function will
  /// provide the list. Since many executables or shared libraries
  /// may depend on the same files,
  /// FileSpecList::AppendIfUnique(const FileSpec &) should be
  /// used to make sure any files that are added are not already in
  /// the list.
  ///
  /// @param[out] file_list
  ///     A list of file specification objects that gets dependent
  ///     files appended to.
  ///
  /// @return
  ///     The number of new files that were appended to \a file_list.
  ///
  /// @see FileSpecList::AppendIfUnique(const FileSpec &)
  //------------------------------------------------------------------
  virtual uint32_t GetDependentModules(FileSpecList &file_list) = 0;

  //------------------------------------------------------------------
  /// Tells whether this object file is capable of being the main executable
  /// for a process.
  ///
  /// @return
  ///     \b true if it is, \b false otherwise.
  //------------------------------------------------------------------
  virtual bool IsExecutable() const = 0;

  //------------------------------------------------------------------
  /// Returns the offset into a file at which this object resides.
  ///
  /// Some files contain many object files, and this function allows
  /// access to an object's offset within the file.
  ///
  /// @return
  ///     The offset in bytes into the file. Defaults to zero for
  ///     simple object files that a represented by an entire file.
  //------------------------------------------------------------------
  virtual lldb::addr_t GetFileOffset() const { return m_file_offset; }

  virtual lldb::addr_t GetByteSize() const { return m_length; }

  //------------------------------------------------------------------
  /// Get accessor to the object file specification.
  ///
  /// @return
  ///     The file specification object pointer if there is one, or
  ///     NULL if this object is only from memory.
  //------------------------------------------------------------------
  virtual FileSpec &GetFileSpec() { return m_file; }

  //------------------------------------------------------------------
  /// Get const accessor to the object file specification.
  ///
  /// @return
  ///     The const file specification object pointer if there is one,
  ///     or NULL if this object is only from memory.
  //------------------------------------------------------------------
  virtual const FileSpec &GetFileSpec() const { return m_file; }

  //------------------------------------------------------------------
  /// Get the name of the cpu, vendor and OS for this object file.
  ///
  /// This value is a string that represents the target triple where
  /// the cpu type, the vendor and the OS are encoded into a string.
  ///
  /// @param[out] target_triple
  ///     The string value of the target triple.
  ///
  /// @return
  ///     \b True if the target triple was able to be computed, \b
  ///     false otherwise.
  //------------------------------------------------------------------
  virtual bool GetArchitecture(ArchSpec &arch) = 0;

  //------------------------------------------------------------------
  /// Gets the section list for the currently selected architecture
  /// (and object for archives).
  ///
  /// Section list parsing can be deferred by ObjectFile instances
  /// until this accessor is called the first time.
  ///
  /// @return
  ///     The list of sections contained in this object file.
  //------------------------------------------------------------------
  virtual SectionList *GetSectionList(bool update_module_section_list = true);

  virtual void CreateSections(SectionList &unified_section_list) = 0;

  //------------------------------------------------------------------
  /// Notify the ObjectFile that the file addresses in the Sections
  /// for this module have been changed.
  //------------------------------------------------------------------
  virtual void SectionFileAddressesChanged() {}

  //------------------------------------------------------------------
  /// Gets the symbol table for the currently selected architecture
  /// (and object for archives).
  ///
  /// Symbol table parsing can be deferred by ObjectFile instances
  /// until this accessor is called the first time.
  ///
  /// @return
  ///     The symbol table for this object file.
  //------------------------------------------------------------------
  virtual Symtab *GetSymtab() = 0;

  //------------------------------------------------------------------
  /// Appends a Symbol for the specified so_addr to the symbol table.
  ///
  /// If verify_unique is false, the symbol table is not searched
  /// to determine if a Symbol found at this address has already been
  /// added to the symbol table.  When verify_unique is true, this
  /// method resolves the Symbol as the first match in the SymbolTable
  /// and appends a Symbol only if required/found.
  ///
  /// @return
  ///     The resolved symbol or nullptr.  Returns nullptr if a
  ///     a Symbol could not be found for the specified so_addr.
  //------------------------------------------------------------------
  virtual Symbol *ResolveSymbolForAddress(const Address &so_addr,
                                          bool verify_unique) {
    // Typically overridden to lazily add stripped symbols recoverable from
    // the exception handling unwind information (i.e. without parsing
    // the entire eh_frame section.
    //
    // The availability of LC_FUNCTION_STARTS allows ObjectFileMachO
    // to efficiently add stripped symbols when the symbol table is
    // first constructed.  Poorer cousins are PECoff and ELF.
    return nullptr;
  }

  //------------------------------------------------------------------
  /// Detect if this object file has been stripped of local symbols.
  //------------------------------------------------------------------
  /// Detect if this object file has been stripped of local symbols.
  ///
  /// @return
  ///     Return \b true if the object file has been stripped of local
  ///     symbols.
  //------------------------------------------------------------------
  virtual bool IsStripped() = 0;

  //------------------------------------------------------------------
  /// Frees the symbol table.
  ///
  /// This function should only be used when an object file is
  ///
  /// @param[in] flags
  ///     eSymtabFromUnifiedSectionList: Whether to clear symbol table
  ///     for unified module section list, or object file.
  ///
  /// @return
  ///     The symbol table for this object file.
  //------------------------------------------------------------------
  virtual void ClearSymtab();

  //------------------------------------------------------------------
  /// Gets the UUID for this object file.
  ///
  /// If the object file format contains a UUID, the value should be
  /// returned. Else ObjectFile instances should return the MD5
  /// checksum of all of the bytes for the object file (or memory for
  /// memory based object files).
  ///
  /// @return
  ///     Returns \b true if a UUID was successfully extracted into
  ///     \a uuid, \b false otherwise.
  //------------------------------------------------------------------
  virtual bool GetUUID(lldb_private::UUID *uuid) = 0;

  //------------------------------------------------------------------
  /// Gets the symbol file spec list for this object file.
  ///
  /// If the object file format contains a debug symbol file link,
  /// the values will be returned in the FileSpecList.
  ///
  /// @return
  ///     Returns filespeclist.
  //------------------------------------------------------------------
  virtual lldb_private::FileSpecList GetDebugSymbolFilePaths() {
    return FileSpecList();
  }

  //------------------------------------------------------------------
  /// Gets the file spec list of libraries re-exported by this object file.
  ///
  /// If the object file format has the notion of one library re-exporting the
  /// symbols from another,
  /// the re-exported libraries will be returned in the FileSpecList.
  ///
  /// @return
  ///     Returns filespeclist.
  //------------------------------------------------------------------
  virtual lldb_private::FileSpecList GetReExportedLibraries() {
    return FileSpecList();
  }

  //------------------------------------------------------------------
  /// Sets the load address for an entire module, assuming a rigid
  /// slide of sections, if possible in the implementation.
  ///
  /// @return
  ///     Returns true iff any section's load address changed.
  //------------------------------------------------------------------
  virtual bool SetLoadAddress(Target &target, lldb::addr_t value,
                              bool value_is_offset) {
    return false;
  }

  //------------------------------------------------------------------
  /// Gets whether endian swapping should occur when extracting data
  /// from this object file.
  ///
  /// @return
  ///     Returns \b true if endian swapping is needed, \b false
  ///     otherwise.
  //------------------------------------------------------------------
  virtual lldb::ByteOrder GetByteOrder() const = 0;

  //------------------------------------------------------------------
  /// Attempts to parse the object header.
  ///
  /// This function is used as a test to see if a given plug-in
  /// instance can parse the header data already contained in
  /// ObjectFile::m_data. If an object file parser does not
  /// recognize that magic bytes in a header, false should be returned
  /// and the next plug-in can attempt to parse an object file.
  ///
  /// @return
  ///     Returns \b true if the header was parsed successfully, \b
  ///     false otherwise.
  //------------------------------------------------------------------
  virtual bool ParseHeader() = 0;

  //------------------------------------------------------------------
  /// Returns a reference to the UnwindTable for this ObjectFile
  ///
  /// The UnwindTable contains FuncUnwinders objects for any function in
  /// this ObjectFile.  If a FuncUnwinders object hasn't been created yet
  /// (i.e. the function has yet to be unwound in a stack walk), it
  /// will be created when requested.  Specifically, we do not create
  /// FuncUnwinders objects for functions until they are needed.
  ///
  /// @return
  ///     Returns the unwind table for this object file.
  //------------------------------------------------------------------
  virtual lldb_private::UnwindTable &GetUnwindTable() { return m_unwind_table; }

  //------------------------------------------------------------------
  /// Returns if the function bounds for symbols in this symbol file
  /// are likely accurate.
  ///
  /// The unwinder can emulate the instructions of functions to understand
  /// prologue/epilogue code sequences, where registers are spilled on
  /// the stack, etc.  This feature relies on having the correct start
  /// addresses of all functions.  If the ObjectFile has a way to tell
  /// that symbols have been stripped and there's no way to reconstruct
  /// start addresses (e.g. LC_FUNCTION_STARTS on Mach-O, or eh_frame
  /// unwind info), the ObjectFile should indicate that assembly emulation
  /// should not be used for this module.
  ///
  /// It is uncommon for this to return false.  An ObjectFile needs to
  /// be sure that symbol start addresses are unavailable before false
  /// is returned.  If it is unclear, this should return true.
  ///
  /// @return
  ///     Returns true if assembly emulation should be used for this
  ///     module.
  ///     Only returns false if the ObjectFile is sure that symbol
  ///     addresses are insufficient for accurate assembly emulation.
  //------------------------------------------------------------------
  virtual bool AllowAssemblyEmulationUnwindPlans() { return true; }

  //------------------------------------------------------------------
  /// Similar to Process::GetImageInfoAddress().
  ///
  /// Some platforms embed auxiliary structures useful to debuggers in the
  /// address space of the inferior process.  This method returns the address
  /// of such a structure if the information can be resolved via entries in
  /// the object file.  ELF, for example, provides a means to hook into the
  /// runtime linker so that a debugger may monitor the loading and unloading
  /// of shared libraries.
  ///
  /// @return
  ///     The address of any auxiliary tables, or an invalid address if this
  ///     object file format does not support or contain such information.
  virtual lldb_private::Address GetImageInfoAddress(Target *target) {
    return Address();
  }

  //------------------------------------------------------------------
  /// Returns the address of the Entry Point in this object file - if
  /// the object file doesn't have an entry point (because it is not an
  /// executable file) then an invalid address is returned.
  ///
  /// @return
  ///     Returns the entry address for this module.
  //------------------------------------------------------------------
  virtual lldb_private::Address GetEntryPointAddress() { return Address(); }

  //------------------------------------------------------------------
  /// Returns the address that represents the header of this object
  /// file.
  ///
  /// The header address is defined as where the header for the object
  /// file is that describes the content of the file. If the header
  /// doesn't appear in a section that is defined in the object file,
  /// an address with no section is returned that has the file offset
  /// set in the m_file_offset member of the lldb_private::Address object.
  ///
  /// @return
  ///     Returns the entry address for this module.
  //------------------------------------------------------------------
  virtual lldb_private::Address GetHeaderAddress() {
    return Address(m_memory_addr);
  }

  virtual uint32_t GetNumThreadContexts() { return 0; }

  virtual lldb::RegisterContextSP
  GetThreadContextAtIndex(uint32_t idx, lldb_private::Thread &thread) {
    return lldb::RegisterContextSP();
  }

  //------------------------------------------------------------------
  /// The object file should be able to calculate its type by looking
  /// at its file header and possibly the sections or other data in
  /// the object file. The file type is used in the debugger to help
  /// select the correct plug-ins for the job at hand, so this is
  /// important to get right. If any eTypeXXX definitions do not match
  /// up with the type of file you are loading, please feel free to
  /// add a new enumeration value.
  ///
  /// @return
  ///     The calculated file type for the current object file.
  //------------------------------------------------------------------
  virtual Type CalculateType() = 0;

  //------------------------------------------------------------------
  /// In cases where the type can't be calculated (elf files), this
  /// routine allows someone to explicitly set it. As an example,
  /// SymbolVendorELF uses this routine to set eTypeDebugInfo when
  /// loading debug link files.
  virtual void SetType(Type type) { m_type = type; }

  //------------------------------------------------------------------
  /// The object file should be able to calculate the strata of the
  /// object file.
  ///
  /// Many object files for platforms might be for either user space
  /// debugging or for kernel debugging. If your object file subclass
  /// can figure this out, it will help with debugger plug-in selection
  /// when it comes time to debug.
  ///
  /// @return
  ///     The calculated object file strata for the current object
  ///     file.
  //------------------------------------------------------------------
  virtual Strata CalculateStrata() = 0;

  //------------------------------------------------------------------
  /// Get the object file version numbers.
  ///
  /// Many object files have a set of version numbers that describe
  /// the version of the executable or shared library. Typically there
  /// are major, minor and build, but there may be more. This function
  /// will extract the versions from object files if they are available.
  ///
  /// If \a versions is NULL, or if \a num_versions is 0, the return
  /// value will indicate how many version numbers are available in
  /// this object file. Then a subsequent call can be made to this
  /// function with a value of \a versions and \a num_versions that
  /// has enough storage to store some or all version numbers.
  ///
  /// @param[out] versions
  ///     A pointer to an array of uint32_t types that is \a num_versions
  ///     long. If this value is NULL, the return value will indicate
  ///     how many version numbers are required for a subsequent call
  ///     to this function so that all versions can be retrieved. If
  ///     the value is non-NULL, then at most \a num_versions of the
  ///     existing versions numbers will be filled into \a versions.
  ///     If there is no version information available, \a versions
  ///     will be filled with \a num_versions UINT32_MAX values
  ///     and zero will be returned.
  ///
  /// @param[in] num_versions
  ///     The maximum number of entries to fill into \a versions. If
  ///     this value is zero, then the return value will indicate
  ///     how many version numbers there are in total so another call
  ///     to this function can be make with adequate storage in
  ///     \a versions to get all of the version numbers. If \a
  ///     num_versions is less than the actual number of version
  ///     numbers in this object file, only \a num_versions will be
  ///     filled into \a versions (if \a versions is non-NULL).
  ///
  /// @return
  ///     This function always returns the number of version numbers
  ///     that this object file has regardless of the number of
  ///     version numbers that were copied into \a versions.
  //------------------------------------------------------------------
  virtual uint32_t GetVersion(uint32_t *versions, uint32_t num_versions) {
    if (versions && num_versions) {
      for (uint32_t i = 0; i < num_versions; ++i)
        versions[i] = UINT32_MAX;
    }
    return 0;
  }

  //------------------------------------------------------------------
  /// Get the minimum OS version this object file can run on.
  ///
  /// Some object files have information that specifies the minimum OS
  /// version that they can be used on.
  ///
  /// If \a versions is NULL, or if \a num_versions is 0, the return
  /// value will indicate how many version numbers are available in
  /// this object file. Then a subsequent call can be made to this
  /// function with a value of \a versions and \a num_versions that
  /// has enough storage to store some or all version numbers.
  ///
  /// @param[out] versions
  ///     A pointer to an array of uint32_t types that is \a num_versions
  ///     long. If this value is NULL, the return value will indicate
  ///     how many version numbers are required for a subsequent call
  ///     to this function so that all versions can be retrieved. If
  ///     the value is non-NULL, then at most \a num_versions of the
  ///     existing versions numbers will be filled into \a versions.
  ///     If there is no version information available, \a versions
  ///     will be filled with \a num_versions UINT32_MAX values
  ///     and zero will be returned.
  ///
  /// @param[in] num_versions
  ///     The maximum number of entries to fill into \a versions. If
  ///     this value is zero, then the return value will indicate
  ///     how many version numbers there are in total so another call
  ///     to this function can be make with adequate storage in
  ///     \a versions to get all of the version numbers. If \a
  ///     num_versions is less than the actual number of version
  ///     numbers in this object file, only \a num_versions will be
  ///     filled into \a versions (if \a versions is non-NULL).
  ///
  /// @return
  ///     This function always returns the number of version numbers
  ///     that this object file has regardless of the number of
  ///     version numbers that were copied into \a versions.
  //------------------------------------------------------------------
  virtual uint32_t GetMinimumOSVersion(uint32_t *versions,
                                       uint32_t num_versions) {
    if (versions && num_versions) {
      for (uint32_t i = 0; i < num_versions; ++i)
        versions[i] = UINT32_MAX;
    }
    return 0;
  }

  //------------------------------------------------------------------
  /// Get the SDK OS version this object file was built with.
  ///
  /// The versions arguments and returns values are the same as the
  /// GetMinimumOSVersion()
  //------------------------------------------------------------------
  virtual uint32_t GetSDKVersion(uint32_t *versions, uint32_t num_versions) {
    if (versions && num_versions) {
      for (uint32_t i = 0; i < num_versions; ++i)
        versions[i] = UINT32_MAX;
    }
    return 0;
  }

  //------------------------------------------------------------------
  /// Return true if this file is a dynamic link editor (dyld)
  ///
  /// Often times dyld has symbols that mirror symbols in libc and
  /// other shared libraries (like "malloc" and "free") and the user
  /// does _not_ want to stop in these shared libraries by default.
  /// We can ask the ObjectFile if it is such a file and should be
  /// avoided for things like settings breakpoints and doing function
  /// lookups for expressions.
  //------------------------------------------------------------------
  virtual bool GetIsDynamicLinkEditor() { return false; }

  //------------------------------------------------------------------
  // Member Functions
  //------------------------------------------------------------------
  Type GetType() {
    if (m_type == eTypeInvalid)
      m_type = CalculateType();
    return m_type;
  }

  Strata GetStrata() {
    if (m_strata == eStrataInvalid)
      m_strata = CalculateStrata();
    return m_strata;
  }

  // When an object file is in memory, subclasses should try and lock
  // the process weak pointer. If the process weak pointer produces a
  // valid ProcessSP, then subclasses can call this function to read
  // memory.
  static lldb::DataBufferSP ReadMemory(const lldb::ProcessSP &process_sp,
                                       lldb::addr_t addr, size_t byte_size);

  size_t GetData(lldb::offset_t offset, size_t length,
                 DataExtractor &data) const;

  size_t CopyData(lldb::offset_t offset, size_t length, void *dst) const;

  virtual size_t ReadSectionData(const Section *section,
                                 lldb::offset_t section_offset, void *dst,
                                 size_t dst_len) const;

  virtual size_t ReadSectionData(const Section *section,
                                 DataExtractor &section_data) const;

  size_t MemoryMapSectionData(const Section *section,
                              DataExtractor &section_data) const;

  bool IsInMemory() const { return m_memory_addr != LLDB_INVALID_ADDRESS; }

  // Strip linker annotations (such as @@VERSION) from symbol names.
  virtual std::string
  StripLinkerSymbolAnnotations(llvm::StringRef symbol_name) const {
    return symbol_name.str();
  }

  static lldb::SymbolType GetSymbolTypeFromName(
      llvm::StringRef name,
      lldb::SymbolType symbol_type_hint = lldb::eSymbolTypeUndefined);

protected:
  //------------------------------------------------------------------
  // Member variables.
  //------------------------------------------------------------------
  FileSpec m_file;
  Type m_type;
  Strata m_strata;
  lldb::addr_t m_file_offset; ///< The offset in bytes into the file, or the
                              ///address in memory
  lldb::addr_t m_length; ///< The length of this object file if it is known (can
                         ///be zero if length is unknown or can't be
                         ///determined).
  DataExtractor
      m_data; ///< The data for this object file so things can be parsed lazily.
  lldb_private::UnwindTable m_unwind_table; /// < Table of FuncUnwinders objects
                                            /// created for this ObjectFile's
                                            /// functions
  lldb::ProcessWP m_process_wp;
  const lldb::addr_t m_memory_addr;
  std::unique_ptr<lldb_private::SectionList> m_sections_ap;
  std::unique_ptr<lldb_private::Symtab> m_symtab_ap;
  uint32_t m_synthetic_symbol_idx;

  //------------------------------------------------------------------
  /// Sets the architecture for a module.  At present the architecture
  /// can only be set if it is invalid.  It is not allowed to switch from
  /// one concrete architecture to another.
  ///
  /// @param[in] new_arch
  ///     The architecture this module will be set to.
  ///
  /// @return
  ///     Returns \b true if the architecture was changed, \b
  ///     false otherwise.
  //------------------------------------------------------------------
  bool SetModulesArchitecture(const ArchSpec &new_arch);

  ConstString GetNextSyntheticSymbolName();

private:
  DISALLOW_COPY_AND_ASSIGN(ObjectFile);
};

} // namespace lldb_private

#endif // liblldb_ObjectFile_h_